Akhilesh S. Tiwari
PhD candidate, Aerospace Engineering · The University of Texas at Austin
Computational Fluid Physics Lab, with Prof. David B. Goldstein
I model gas flows where the continuum assumption breaks down — rocket plumes expanding into vacuum, transport inside low-pressure chambers, spacecraft surfaces in low Earth orbit. My work couples continuum CFD to direct simulation Monte Carlo across four orders of magnitude in density, and runs at scale on national supercomputers.
Research
- Rarefied gas dynamics & DSMC Variable soft sphere collisions, Knudsen-based adaptive refinement, continuum-breakdown criteria, gas–surface interaction and accommodation modelling.
- Coupled continuum→rarefied simulation OpenFOAM to SPARTA pipelines spanning collisional nozzle flow through to free-molecular vacuum transport, on up to 448 MPI ranks.
- Plume impingement & orbital debris Contactless detumbling of uncooperative targets by thruster plume momentum transfer, including off-pointing, atmospheric and backscatter sensitivities.
- Surrogate-based design optimisation Gaussian-process surrogates and Bayesian optimisation over expensive kinetic solvers, with cheap screening filters and documented validity limits.
Selected publications
- A. S. Tiwari, A. Moreno, et al. “Space debris detumbling via plume impingement: off-pointing, atmosphere, and backscatter effects.” Acta Astronautica 247:691–705, 2026.
- S. Nair, J. Neal, A. Moreno, A. S. Tiwari, et al. “Computational and experimental investigation of nozzle plume impingement for detumbling orbital debris.” Journal of Spacecraft and Rockets, 2026.
- A. S. Tiwari, S. Nair, D. B. Goldstein. “Single- and multinozzle plume impingement to detumble space debris.” Journal of Spacecraft and Rockets, 2024.
- A. S. Tiwari, S. Kumar. “Effect of acoustic perturbation on vortex street transition in a flowing soap film.” Physics of Fluids, 2023.Featured article
- A. Burtsev, F. Muhammad, A. S. Tiwari, et al. “Effects of modeling measured surface roughness on orbital drag in low Earth orbits.” AIAA SciTech Forum, 2026.
- A. S. Tiwari, A. Moreno, et al. “Optimizing space debris detumbling using DSMC: plume impingement dynamics and sensitivities.” AIAA SciTech Forum, 2025.
- R. You, A. S. Tiwari, S. A. Kinnas. “Viscous vorticity equation (VISVE) model applied to oscillatory turbulent flow around a cylinder.” SNAME Offshore Symposium, 2022.
Dance of a vortex street
Awards
- 2024–25Charles M. Simmons Endowed Presidential Fellowship in Engineering, UT Austin
- 2025Livermore Lab Foundation Award, Lawrence Livermore National Laboratory
- 2023Featured Article, Physics of Fluids
- 2021–24Cockrell School of Engineering Scholarship, UT Austin
- 2018All India Rank 46, GATE Aerospace Engineering (98.88th percentile)
- 2017Silver Medalist, Aeronautical Engineering, Hindustan University